1. Field of the Invention
The present invention relates to a liquid crystal display driving circuit, and more particularly, to a liquid crystal display driving circuit with low current consumption, which can reduce an amount of current consumed during charging and discharging processes when driving a liquid crystal display.
2. Description of the Related Art
Liquid crystal displays (LCDs) refer to devices which display image data by passing light through liquid crystals by using a characteristic that the alignment of liquid crystal molecules is changed depending upon an applied voltage.
In circuits and systems for driving such LCDs, current consumption is regarded as one of very important factors. If current consumption increases, as the temperature of an LCD driving circuit and system rises, the reliability and the lifetime of the LCD driving circuit and system are likely to be degraded and shortened. Also, if current consumption increases in an LCD driving circuit and system applied to a mobile terminal, as the available service time of a battery is shortened, the run time of the mobile terminal is shortened.
FIG. 1 is a view illustrating a current consuming process when a conventional LCD driving circuit drives a panel.
In order for an LCD driving circuit to drive an LCD panel, the data lines of the LCD panel should be driven, and in this process, current consumption occurs.
The data line of the LCD panel serves as an R/C load composed of a resistor and a capacitor when viewed in terms of an equivalent circuit. In order for the LCD driving circuit to drive the LCD panel, the R/C load should be charged and discharged.
That is to say, when it is necessary to drive a level higher than a previous level, the LCD driving circuit should be supplied with charges at a first voltage VDD and charge the R/C load, and when it is necessary to drive a level lower than a previous level, the LCD driving circuit should discharge the charges charged in the R/C load through a second voltage VSS.
In order for the LCD driving circuit to drive the LCD panel, this process should be continuously repeated, during which current is consumed.
When the LCD driving circuit drives the LCD panel according to the conventional art as described above, because the charges supplied at the first voltage VDD are used only once and are discharged to the second voltage VSS, current consumption of the LCD driving circuit and system increases, and due to this fact, a temperature rises.
If current consumption increases and a temperature rises, the reliability and the lifetime of the LCD driving circuit and system are likely to be respectively degraded and shortened. Also, in the case of an LCD driving circuit and system applied to a mobile terminal, as the available service time of a battery is shortened, the run time of the mobile terminal may be also shortened.